Twist-drill



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GEORGEiF. LEONARD, OF FAIRMONT, WEST VIRGINIA.

TWISTnDjRiLLAND SOCKET.

SPECIFICATION forming part of Letters Patent No. 611,494,datedvSeptember 27, 1898.

Application filed llpril 30,1898. Serial No. 679,341. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE F. LEONARD, a citizen ofthe United States, residing at Fairmont, in the county of Marion and State of West Virginia, have invented new and useful'Improvements in Twist-Drills and Sockets, of which the following is a specification.

This invention relates to improvements in twist-drills and sockets. As ordinarily constructed the drill-shank terminates in a iiat tang, which enters a transverse slot in the socket for holding the drill fromy turning. Such holding means being at the extremity ofthe shank, also at its smallest diameter, is frequently not sufciently strong to withstand the strain, with the result that the tang either twists entirelyoff or the socket-slot reams out and permits the drill to turn. Various means count of weakness, liability to disorder, projection of parts" preventing the socket from The object of the present invention is torunning close to the work, (lac.

overcome the difficulties noted by forming the parts with flat or other engaging or holding surfaces entirelywithin the socket and of suiiicicnt extent to preclude possibility of twisting.

The invention con'sists in the novel features of construction hereinafter fully described and claimed, and illustrated by the accompanying drawings, in whichl Figure l is an elevation, partly in section, of a socket and upper portion of a drillof my improved form. Fig. 2 is a cross-section on line y y of Fig. l. Fig. 3 is an elevation of the socket, and Fig. 4l a detail view of the shank end of a drill. 4

Socket A is formed withthe usual tapering bore A to receive tapering drill-shank B, the extremity of the latter forming tang C, which enters transverse slot D in the socket, and it is to reinforcing this connection that the present invention is directed. To this end socket A is formed on one side of its axialf line with transverse vertically-elongated slot E, partially coincident with bore A', and fixed therethe hold of the socket upon the drill is suchl that it is impossible for the drill to twist or work loose. Neither the strength of the drill vnor its use in sockets of ordinary form are impaired by Vthe fiat on its shank. The drill is held absolutely true, as the shank-flat occursentirely within the socket, the end of the latter being closed by a circular or unbroken section of the shank.

I do not limit myself to flat engaging or locking surfaces on the drill and socket, and it will be understood that the improvement is applicable to other tools and sockets or chucks thanthose here described and shown.

The improvement is simple and inexpensive and drills and sockets now in use may be' readily conformed thereto.

It will be observed that the usual external contour of the socket is preserved, and that the same is not encumbered with set-screws and other projecting and movable parts, and that the socket is constantlyready to receive or discharge the drill.

Having thus fully described my invention,

what I claim, and desire to secure by Letters Patent, isn l. The combination with a socket having a bore circular in cross-section, the socket being formed with a transverse slot intermediate the ends of the' circular bore, one side of the slot being coincident with the bore, and a key fixed in the slot and having a flat surface which interrupts the circular contour of the bore,- of a drill having a circular shank formed with-a longitudinal hat extending to a point beneath the flat transverse key when in position in the socket-bore, substantially as shown and described.

2. The combination with a sock-et having a circular longitudinal bore terminating 'in transverse slot D having fiat sides, the socket being formed beneath slot D with transverse slot E at one side of the longitudinalcenter of the socket but coincident with one'side of the socket-bore, and key F secured in slot E,

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of the drill having tang O at the extremity of its shank to enter slot D, the drill-shank being attened downward from its extremity on one side to pass key F, but liatly engage the same so as to relieve the drill-shank and tang C thereof of torsional strain, substantially as shown and described.

In testimony whereof I have hereunto set my hand in presence of two subscribing Witnesses.

GEORGE F. LEONARD. Witnesses:

H. C. SAMPLE, WM. A. OHLEY. 

